What kind of battery check did you do? Measuring the voltage always indicates fully charged if there has been any charging in the last 8 hours. A business selling batteries will usually do a load test free of charge. This will take some time and leave the battery discharged as they charge it up and then drain it through a load, measuring the energy released.
I killed my first set of batteries. Now I have a battery monitor that lets me see the level of charge all the time. I never let it go below 50 per cent because that damages the batteries. I know how well it is charging and discharging.
$25 Bay battery monitor that works well